Harmful bacteria
Raw milk from any animal may be contaminated with illness-causing bacteria including shiga toxin-producing E. coli (STEC), Listeria and Campylobacter . These bacteria most commonly cause severe diarrhoea and vomiting, but occasionally some have been linked with more serious complications that include abortion, paralysis, meningitis, and serious kidney problems in children.
Despite these hazards, there are people who choose to consume raw milk. In 2014 in New Zealand:
- raw milk was associated with 10 outbreaks that affected 41 people.
- 9 of the outbreaks involved children under 15 years old (6 involved children aged 2 or younger).
- 2 children developed Haemolytic Uraemic Syndrome (HUS) – a severe complication of STEC infection that may lead to kidney failure.
Raw milk may also be a source of tuberculosis (Tb).
New regulations – 1 March 2016
New regulations will require registered farmers to sell raw milk directly from the farm gate or by home delivery. There will be no more collection points. Customers buying raw milk will be asked to supply their contact details, so they can be reached if a batch of milk fails hygiene or pathogen testing.
There will be a transition period for existing producers up until 1 November 2016.
Nutrition – pasteurised versus non-pasteurised
Pasteurisation is a simple process where milk is heated to kill bacteria. There's more than one technique but, in New Zealand, suppliers warm milk to 72 degrees Celsius and hold it at that temperature for 15 seconds. The process has minimal effect on the nutritional qualities of milk:
- Fat and proteins: minimal effect on composition.
- Minerals: no effect.
- Vitamins: almost no effect on riboflavin, B6, B12 or folate; 10% loss of vitamin C.
- Protein: no impact on nutritional quality.
- Enzymes: minimal effect when using the New Zealand pasteurisation technique.
There's no substantial scientific evidence to suggest raw milk offers any health benefits over pasteurised milk.
The MPI assessment reviewed by the Office of the Prime Minister's Chief Science Advisor concluded "the claimed health benefits of raw milk compared with pasteurised milk are, for the most part, not backed by scientific evidence".
Can I get risk-free raw milk?
No – you can't. Potentially harmful bacteria live in the gut of many healthy animals and are consequently everywhere on farms. They can dwell on clean-looking surfaces, such as milking cups, and spread from there to the milk.
While the best production and processing practices will reduce the health risks to consumers, they can't remove them completely. There's no easy way to tell if raw milk is carrying bacteria. It has to be analysed in the laboratory.
People at greatest risk from raw milk
Raw milk is a risky food for anybody who consumes it, but some groups of people are especially vulnerable, including:
- young children and babies
- the elderly
- pregnant women
- people with a weakened immune system.
The immune system can be weakened by surgery, certain medications, and long-term illnesses.
To avoid getting sick
In the home, the most reliable way to avoid getting sick is to heat raw milk to 70 degrees Celsius and hold it at that temperature for 1 minute. If you don't have a thermometer, heat the milk until it reaches boiling (or scald the milk).
Who to contact
If you have questions about raw milk, email info@mpi.govt.nz .